Remote control system



Marh 28, 1944- A. N. GoLDsMrrH REMOTE CONTROL SYSTEM l Filed Oct. 20,1939 4 Sheets-Sheet l WWK n.

March A28, 1944- A. N. GoLDsMITH ,A 2,345,472

REMQTE CONTROL SYSTEM Filed Oct. 20, 1939 4 Sheets-Sheet 2 IN TOR ALFREDN. DSM/7H E* M M ATTORNEY T March 28, 1944.

' REMOTE CONTROL SYSTEM Filed oct. 2Q, 19:59 4 sheets-Sheet s my mh ummy n v if w 97 97 ya /02 a fa/ K 00 99 701 lbs ,v INVENTOR ALFRED N.GOLDSM/TH ATToRNEY A. N. GoLDsMlTli 2,345,4724

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March 28, 1944. A, N GOLDsMn-H 2,345,472

REMOTE CONTROL SYSTEM Filed Oct. 20, 1939 4 Sheets-Sheet 4 INVENT ALFRED/v. Gow rf/l ATTORNEY Patented Mm.v 1944 REMOTE CONTROL SYSTEM Ain-ea N.Goldsmith, New York, N. Y., minor to Radio Corporation oi' America, NewYork, N. Y., a corporation of Delaware Application oezoberzo, 1939,serial No. 300,326 l '1 claims. (c1. 25o-2) The presentixiventionrelatesbroadly to remote control systems which they may be'used,

-In one particular embodiment of the invention modulated supersonicwaves are used to remotely control a radio receiver.

Among the objects of the invention may be mentioned the following:

1. To enable the remote control of a radio receiver (or transmitter orother similar controllable device) within a given room without specialor direct electric wiring between the control device and the controlledreceiver.

2. `To permit such control with a multiplicity of selective proceduresas, for example, turning the receiver on"and oll', tuning the receiverin one or both directions, and the like.

3. To obtain the above control regardless oi' the 4. To obtain suchcontrol even in the case of battery-operated receivers having noconnection to electric circuits.

5. Toobtain such control alternatively with or outside electric powersupply or circuit.

6. To secure such control regardless of the relative positions of thecontrol device and the receiver in the room.

7. To secure such control without acoustic interference withpersons inthe room or reproduced v music or speech.

While other objects of the invention will be apparent from a reading ofthe following detailed speciiication, it is apparent from the precedingthat th'e aims ofthe present invention are unusually broad. f

In one method of carrying out the presentinvention use `is made of soundimpulses, waves or trains radiated from the control device and receivedby the receiver which is at all times activated to the extent necessaryto respond to such sound impulses. In the present specification the termimpulses is intended to include waves, trains or other formed groups orsequences of groups of sound whether audible or inaudible.

The invention may be best understood by referring to the accompanyingdrawings and the iescription of the arrangements disclosed there n.

In said drawings,

Fig. 1 illustrates in schematic form, va diagram -nature of the powercircuits feeding the receiver.

\ without connection of the control device to any i which will bereferred to in describing the general aspects of the invention;

Fig. 2 illustrates one form of an electrically operated modulatedsupersonic oscillator;

Fig. 3 illustrates in schematic form an arrangement for diiusing thewaves emitted by a device such as disclosed in Fig. 2;

Fig. 4 illustrates an oscillator using a similar drive to thatillustrated in Fig. 2 but employing a wide angle radiator;

Fig. 5 is a representation of ya device for producing control waves bymechanical excitation;

Fig; 6A illustrates another form of a mechanically excited oscillator;

Fig. 6B is a sectional view of the oscillator shown in Fig. 6A;

Fig. 7 is adiagrammatic showing of a device using a siren method oimodulation; and.`

Fig. 8 vis al diagrammatic illustration of an ar-` rangement which'maybe used to receive the 00ntrol waves.

In the system illustrated in Fig. 1, Als an OS- cillator which may besupplied with power either from an A. C. or D. C. power supply availablefrom a power outlet in the room in which it is f located or if desiredpower may be supplied from a self-contained battery or if desired thepower ferred. The oscillator may be of the tube type,

ofthe crystal type, of the magnetostrictive type or of the mechanicalvibrator type.

In order to enable appropriate control signals to be sent there isprovidedthemodulating.control-B which controls the 'oscillator A.Physically, the control may be by knobs, buttons, and the like. The modeof control may be either by amplitude modulation or frequency modulationor.

f a combination of these. The control may involve a setting for on-ofioi' the receiver and a'reversible-motor tuning control or else acontinuous-rotation tuning motor control,.or the equivalent of these,together with such added controls las may seem desirable (example, inthe case of the sonic radiator C. This may be .any type of direction ofradiation controllable (f or example l toward the receiving set).

matic frequency control or not, butshould preferably have this feature.vThe drive motor I will In the drawing, D indicates the radiated sonic Ywaves between the control device and the receiver. Infra-sonic or,ultra-sonic waves are used because these do not interfere with thepersons in the room and further because these frequencies fall outsideof the range of frequencies acoustically radiated by the receiver andcan therefore be selectively received at the receiver during the timethat the receiver is in operation,

lthus enabling changes in its operation to be performed withoutinterference from the sound which is radiated by the receiver itself.

In the right hand portion of Fig. 1 is shown in a general manner asuitable arrangement at the receiving set for eilectuating the control.The control signals are received by a sonic receiver or detector E whichmay be any type of sound receiving or detecting device suitable for thefrequency range in question and of adequate sensitivity. lThus it may bea telephone transmitter of the electro-dynamic, electro-static.microphonic, or piezo-electric or similar type. It may be theloudspeaker of the receiving set provided such loudspeaker issuillciently responsive to the control frequencies. It may be thehighfrequency unit (tweeter") of the receiving loudspeaker provided thisis sensitive to the frequencies used. Or it may be the low frequencyunit of .the receiver loudspeaker. It may be made directional ornon-directional It may be connected to a power supply for energizing oramplifying the response. or it may be not so connected.

It may be sharply resonant or broadly resonant to the incoming controlfrequencies. If it is made sharply resonant, ,it will probably be moresensitive but will build up in` response more slowly. It can be changedfrom sharp to broad resonance or vice versa by the incoming signals thusaltering its sensitivity.

The output of thesonic detector E passes through a filter F the functionof which is to permit only control frequencies to reach the controllingmechanism of the receiver. The lter.`

will be of the low-pass type for infra-sonic control signals or of thehigh-pass type for ultrasonic control signals. The ilter may be eitherelectrical or mechanical.

The filter output passes into the amplier orv control G which may besupplied with power locally as indicated in the drawings. The amplifierin question may operate by amplitude varia-v tion control or it may beprimarily responsive to a frequency or frequencies through resonantresponse.

The output of the amplier G acts upon and energizes the remainingportions of the receiver control. Thus the output of the amplifier maybe used to control the on-oil switch H with an intervening relay ifrequired. It may also control with a relay as required the tuning motorI.

The receiver J contains the power unit K which is controlled by theon-oii switch H. The power supply of devices E andG, if required, isalways on. Accordingly any tubes in E and G, if used, are of suchtypes'as to require minimum power to'energlze them and to give a maximumchange in the controlled energy for minimum received excitation.

The receiver J may bev provided with autopacities.

have a starter relay as required and as mentioned above. It may be madereversible or non- A reversible in its control.

The drive motor I controls the tuning device L in the receiver; Thistuning device may be a group of variable capacities, a group ofyvariable inductances, a combination of these, and

wave-range switching means as required. The tuning may therefore beeitherwone involving electro-mechanical devices (for example,a vari-`able condenser bank) or the tuning may be of the straight electronictype whereby inductances or capacities or a combination of these arereflected through a tube into a tuned circuit or modied in amount by atube or tubes suitably connected to such inductances and ca- Orcombination electro-mechanical and electronic tuning may be used.

For generating supersonic oscillations which are modulated at eithersub-audible or superaudible frequencies various arrangements may beused. Such oscillators may be either electri` cally or mechanicallyexcited or a combination of these. While electrically operated remotecontrol stations require a source of electric power they have theadvantage that there is no demand for power upon the person handling theremote control. One such form of supersonic modulated oscillator isillustrated in Fig. 2. It will be understood however thatl theelectromagnetic form of oscillator having a small conical radiator ofair Waves illustrated in Fig. 2 ispurely The form shown in Fig.l2 isessentiallyl an eleco trically modulated supersonic air wave radiator.The two cones I5 and I1 are joined by a thin cylindrical member 2i onwhich is woundl the motor coil I5, the'terminals of which are I3 and I4.The coil I5 surrounds the end portion I8 of the core II which may beeither a permanent magnet of maximum strength or which may be wound withthe coil 'I fed by direct current applied across terminals 6 and 8 andtherefore magnetic. If an electric current of supersonic frequency, e.g., 20 kilocycles, is fed. into the coil I5 through. flexible conductorsfrom the terminals I3, I4, the two cones I6 and I1 `will be-caused tovibrate simultaneously in the directions indicated by the arrows I9, 20.It is not believed necessary here to show anyfmeans for flexiblysupporting the cones in question since such means are well known in theloudspeaker art. It will be noticed that the field from the core II isfor example vertically up through the upper half of coil i5 andvertically downward through the lower half ci' coil I5, assuming northpolarity of the core within the coil and south polarity of the adjacentf ends of the yokes 9, I0. The cones I6 and il' will then be asupersonic air wave radiator.

Coils 3 and 5 may be wound as shown on the yoke and a sub-audiblecurrent, e. g., of 30 cycles and of suitable amplitude may be'passedthrough coils 3 and 5 from terminals I and 2. The magnetic flux throughcoil I 5 resulting fron the curcoils l and l in place o! the 30 cyclelsub-audible frequency current there would be littlel air wave radiationfrom .these small cones aty so low a frequency and, of course, noaudible sound. The

current in coils l and l does however change the magnetic condition ofthe yoke l, Il and the.

Thus, it brings these magnetic elements tion in the-other 4half of thecycle of current As a result the twentythrough coils I and 5. kilocyclefield of coil I5 interacts with a second field of frequency of 30 cyclesand'accordingly the amplitude oi' the oscillations of cones It and l1 at20 kilocycles is modulated by the 30 cycle current in coils 3 and i.

In the operation of a device such as that shown in Fig. 2, it willv beappreciated that to selectively control the. operation o! a plurality ofdevices which are located at a remote point, it is only necessary toemploy dlierent modulating frequencies in a selective manner, that is,assigning a certain action to be performed at the remote point to eachmodulating frequency or combination of modulating frequencies andmodulating the transmitted energy by the particular modulating frequencyor frequencies corresponding to the action desired to be performed atthe remote point. At the remote point the transmitted control energy isreceived and demodulated. The products of demodulation are then suitablysegregated and used for control'purposes such as to operate relays andthe like.

It may be mentioned parenthetically that a system of supersonic andinaudible telephony by air waves may be based on this principle byfeeding the telephone currents into terminals I and 2. However, in thiscase the supersonic oscillations must be made intense and the straightline portion of the magnetization curve of the yoke and core must beused to avoid non-linear modulation and consequent rectification andaudible speech radiation.

It is appreciated that normally supersonic air wave radiation has ahighly directional nature.

Figs. 3 and 4 of the drawings illustrate methods of modifying thishighly directional nature. One

method of modifying the highly directional radiconnecting element 2| oi'Fig. 3 corresponds to' the connecting element 2| of Fig. 2. It is to beunderstood, though not illustrated, that in Fig. 3

the element 2| carries a motor coil such as,coil I 5 of Fig. 2.Reilectors 38 and 31 which are shown as frustra of cones with theirsmaller openings in juxtaposition, are placed surrounding the cones Itand I1 respectively. The arrows Il and 4I have been drawnin Filz.` 3 inrepresent the direct air wave radiation resulting from the motion ofthecones. Supersonic waves renected from the frustra 36 and 31and'diversing outward are shown by the arrows 42, Il, u and II. It isrecognized that interference phenomena between radiation from one or twocones vand reflective radiation may occur but the nnite magnitude of theoscillators and reflector as well as thereceiv- In the form ofmulti-directional or wide angle supersonic radiator illustrated in Fig.4, the radiator is shown as a cylindrical surface," which is fastened atone end 02 and which is attached to the motor element 5I arranged tovoscillate at supersonic frequency. A spring restoring element 51 isshown as fastened at Il. If the radiator il is made f appropriatelysmall dimensions and suitable mass and elasticity it will `oscillate inthe directions shown by the arrows Il and 6l l and will radiateconsiderable amounts of supersonic energy in a wide angle of directions.The

coils` 3 and 5, 1 and l5 of Fig. 3 correspond to the coils in Fig. 2bearing the same numbers and the yokes l and Ill and the core Il oi'Fig. 4 oorl'o, respond to the same elements of Fig. 2.

As previously pointed out it is sometimes desirable to avoid the useofelectric power'at the remote point. Under these circumstances itbecomes necessary to have available a powerful source of supersonic airwaves produced by mechanical excitation. These mechanically generatedsupersonic waves may also be modulated at a sub-audible, audible orsuper-audible'frequency. One form ofsuch oscillator is shownschematically in Fig. wherein Il is a vibrator of any suitable typewhich is capable of producing supersonic vibrations when violentlystruck by means of a hammer 12 which is capable of striking element Ilwhen swung about its Vpivot point 15. The hammer 12 is operated by meansof a key or lever 11 against the .force oi a spring 1l`which is attachedbetween a lugv on the `key and casing 1l. Element Il is mounted lon acomparatively thin metall sheet 1l which is held atv the preceding it isseen that the supersonic oscillator n is oarrled on Ian audio oscillatorn and l accordingly the supersonic waves passing outward through theholesor slots l1 in box or enclosure 18 which may be composed of wood,will b'e to'some extent modulated by the vibration frequency of 1i. Aspreviously inferred the vibration frequency of 1| may be `sub-audible,audible or super-audible. The arrangement shown in Fig. 5 constitutes anassociation of a supersonic oscillator, a lower frequency oscillator,and a common impulse excitation means for both.

In the operation` of the device shown in Fig.

5, depression of key I1 causes counter-clockwise rotation of hammer 12about its pivot point 1i against the force'of spring 1I. continues untilthe continued downward movement of 'key 'I1 causes arm to slip oil ofshoulder i1! thereby releasing-al1 oil the mechanical energy stored upby .spring 14 which causes the hammer 12 to strike vibrator Il viooolently. sp1-lng u tends to bl-l book the llammer to its normal releasedposition. When key 11 is released it returns to its normal releasedposition through the action of spring 18. Arm Il is pivoted on the key11 and is held resiliento5 ly against a suitable stop by the action of aspring 1l. vThis is for the purpose of permitting arm I8 to ride overshoulder 13 on the^return movement of key 11.

Another form of possible moo'llanloal oscillator' for both supersonicand lowel frequency oscillation with modulation of the supersonicfrequency is shown schematically in Figs. 6A and 6B. Referring-to Fig.6A it will be seen that there is provided a pair oftorsional oscillators0i and Il. These oscillators are hollow or solid This movement 'flatportions |04 of. vanes arrangement the diaphragm `any suitable means nothere ing supersonic waves. the generated supersonic waves in thearrangecylinders. y The oscillator. 9| is preferably .rigidly fastenedatits bottom surface to a suitable mounting' ring 92 which in turn isresiliently mounted by means of spring clips 93, 93 to ,a base plate 94.The arrangement is such that oscillator 9| canbe twisted by impact so asto cause it to oscillatein the directions indicated 9| is provided withsmall vanes 99 while Athe,

oscillator 98 is provided with small vanes. |00. These small vanesbecome air wave radiators. The whole structure is enclosed within 4asuityable housing 91 which is provided with' a plurality of .slots oropenings |0.| in registration with the vanes 99. 'Ihe oscillator98 isprovided` with an impact block |02 against which hammer 'I2 operates.Hammer 12 is operated by depression of key 11 similarly in every way tothe arrangement described in connection with Fig. 5.

As indicated 4in Fig. 6B it is possible to cause the supersonicradiation from oscillator :98 to travel" outward through openings in thecasing 91 which may be blocked or opened by the 99 thus modulating suchsupersonic frequencies by the frequency of oscillator 9|.

Still another method of modulating the supersonic vibrations isschematically indicated in Fig.

7. 'lhis arrangement applies either to electrical- `ly excited ormechanically excited supersonic .waves In Fig. 7 the enclosure 3 isprovided -witha series of holes or slots H2. A diaphragm H8 'carries thecylindrical element 9 which may be part of it on its outer portion inapproximate registry.with the openings ||2. I f in such an ||8 is causedto vibrate through the attachment elements I9 by shown and in the Yimpulses are then fed into a tuned circuit |40,

|4|, |42,4 |43 which may in turn be tuned to the modulatingfrequency,-e. g., 30 cycles (which modulating frequency may be audible,sub-audible or super-audible). This last named tuned circuit is in turncoupled to rectifying circuits |44,

. |45, the rectified output of which passes from 1ead&|49, Nl into thecontrolling relays orsimilar elements.

If a receiving element of the type shown in Fig. 5 is provided, that is,if the receiving element is responsive to both supersonic and lowfrequency air waves, the modifications of the circuit of Fig. 8 arebelieved to be obvious therefrom. In this case the doubly resonantreceiving system will produce an output which can be withdrawnpreferably in the form of currents of modulated supersonic frequenciesor in the form of two currents one of which is supersonic in frequencyand the other of which is of a lower frequency. The selection of suchcurrents, their amplification and their rectification, together withtheir utilization in appropriate relay systems need not be furtherdescribed herein. Y

It is thought to beobvious from. the above discussion that it is theintent of the receivers described herein to respond to modulatedsupersonic air waves and effectively to utilize resonant response to thesupersonic frequency and also to the lower frequency of modulation inorder to minimize false (indications and to give a maximum number ofpossi-ble indicating signals from a given group of frequencies in theremote control station.

I claim:

1. The steps in a method of remote control which comprise generatingaerodynamic wave energy of a low supersonic frequency, modulating saidenergy of supersonic frequency with energy .of a sub-audible frequency,radiating the thus modulated energy of supersonic frequencyfasairbornetfree wave energy, receiving the said airdirections indicated bythe arrows H5, lthe exit of supersonic Waves through openings I2 will befacilitated or retarded in substantial synchronism with the oscillationsof ||8. Essentially this arrangement is a siren method of modulat- Itmay be added that ment shown in Fig. 7 may be produced in any well knownmanner, as, for instance, bymeans of a pneumatically-operated device. Itis obvious from the above that the arrangement shown in Fig. 7 combinesa pneumatically-operated supersonic oscillator and a siren or Amobilegate valve type modulator at sub-audible, audible or superaudiblefrequencies.

Suitable receiving means for waves transmitted` by any of the foregoingarrangements may take the same form as the radiators of saidarrangements. If a supersonic oscillator 'alone is used as a receiver anarrangement such as that indicatedin Fig. 8 may be utilized. In saidgure the receiving oscillator |22 carries the coil |23 in a constantmagnetic field excited by coil |30 through yoke 2| and core 3|. Currentof modulated supersonic frequency will flow through condoctors |24, |25into the tuned circuit |34, |35

sonic modulated/impulses are produced. These borne free wave energy,demodulating the received energy, selecting from the demodulated energythe modulating frequency component of the received energy, and utilizingthe resultant energy output for remote control purposes.

2. In a system for the remote control of an element` of a radio receiveror the like, meansv for generating Wave energy of a'low supersonicfrequency, means for generating wave energy of a sub-audible frequency,means for modulating the wave energy of low supersonic frequency by theWave energy of sub-audible frequency, means for radiating the resultantmodulated supersonic frequency energy as aero-dynamic free wave energy.means located adjacent said radio receiver forvreceiving anddemodulating the radiated free wave energy. means for selecting fromthedemodulated energy the modulating frequency component of the receivedenergy, and means utilizing the latter to control said element of theradio receiver or the like.

`3. In an aero-dynamic remote control system, means for generatingelectrical energy of a superlSonic frequency, means for generatingelectrical energy of a lower frequency, means for modulating theelectrical energy of supersonic frequency and |36. This tuned circuit iscoupled lto a recti- 'Y .fying circuit |31, |38, |39 wherein rectifiedsuperbyjthe electrical. energy of lower frequency and means forradiating the resultant modulated supersonic frequency energy asair-bornefree wave energy, said last named means comprising a magneticcircuit provided with -a gap, a surface radiator vof supersonic energy,.a coil system mounted in said gap and rigidly attached to said radiator,means adapted to connect said coil system across the supersonicfrequency generating means. and means for exciting said magnetic circuitby the generated modulating frequency energy. n f' 4. In an aero-dynamicremote control system, means for generating electrical energy of asupersonic frequency, means for generating electrical energy of a lowerfrequency, means for modulating the electrical energy of supersonicfrequency by the electrical energy of lower frequency and means forradiating the resultant modulated supersonic frequency energy asair-borne free wave energy, said last named means comprising a magneticcircuit provided with a gap, a 'surface radiator of supersonic energy, acoil system mounted in said gap and rigidly attached to said radiator,means adapted to connect said coil system to the source of supersonicfrequency energy,

means for exciting said magnetic circuit by the electrical energy of themodulating frequency, direct current energizing` means electricallyasso-1 ciated with said magnetic circuit whereby the latter is affectedas to ux and permeability only by a constant excitation througndirectcurrent.

5. In an aerodynamic remote control system, a source of electricalenergy of a supersonic frequency, a source of electrical energy of alower frequency, a unitary device for modulating the supersonicfrequency energy by the lower frequency energy and radiating theresultant modulated supersonic frequency energy as air-borne free waveenergy, said device comprising a magnetic circuit provided with a gap, asurface radiator and a coil system mounted in said gap andrigidly'attached to said radiator, means for connecting the coil systemto said source of supersonic frequency energy, and means for excitingsaid magnetic circuit by energy derived from said source of modulatingfrequency.

6. In a system for the remote control of an element of aradio receiveror the like, means for generating electrical energy of a low supersonicfrequency.'I means for generating electrical energy of a sub-audiblefrequency, means for modulating the electrical energy of .low supersonicfrequency by the electrical energy of subaudible frequency. means forradiating the resultant modulated supersonic frequency energy asaerodynamic free wave energy, means located adjacent said radio receiverfor receiving and demodulating the radiated free wave energy, means forselecting from the demodulated energy the modulating frequency componentof the received energy, and means utilizing the latter tc control saidelement of the radio receiver or the like.

7. In a system for the remote control of an element of a radio receiveror the like, means for generating aerodynamic energy of a low supersonicfrequency, means for modulating said energy of low supersonic frequencywith energy of a sub-audible control frequency, means for radiating theresultant modulated supersonic frequency energy as air-borne free waveenergy, means located adjacent said radio receiver for receiving anddemodulating the radiated free wave energy, means for selecting from thedemodulated energy the modulating frequency component of the receivedenergy, and means utilizing the latter to control said element of theradio receiver or the like. q

' ALFRED N. GOLDSMITH.

